Michelle Dockery as Lady Mary, left, chats with Joanne Froggatt as Anna Bates in a scene from "Downton Abbey." / Nick Briggs, Carnival Film & Television Limited 2013 for Masterpiece

by Ann Oldenburg, USA TODAY

by Ann Oldenburg, USA TODAY

WARNING: If you haven't yet watched Sunday's Downton Abbey (Episode 2 of Season 4), stop reading now, as this story discusses a major plot point.

For starters, the episode carries a warning, saying it "contains scene which may not be suitable for all audiences."

All begins in a festive way. It's a house party at Highclere Castle!

Lady Mary even manages to muster up a smile.

But that's not the controversial plot point. The "shocker" scene, as it has been referred to in several recaps, unfolds when Anna the maid, played by Joanne Froggatt, is alone in the kitchen with visiting Lord Gillingham's valet, Mr. Green (Nigel Harma).

The two had been playful with each other, but during this dark meeting, he turns aggressive, hitting her, shoving her into a nearby room and raping her. Her screams go unheard as the rest of the house is upstairs listening to real-life opera star Kiri Te Kanawa sing Puccini's O Mio Babbino Caro. A sobbing and bloodied Anna tells only Mrs. Hughes (Phyllis Logan) what has happened and doesn't want anyone, especially her husband, Mr. Bates (Brendan Coyle), to know.

When this episode was shown in Britain last October, audiences were stunned and much was made in the press about Downton doing a rape scene. The BBC reported 60 complaints were made to British network ITV about the episode. The Daily Mail quoted fans who called it "rather nasty" and "morally reprehensible."

Show creator Julian Fellowes told the BBC then, "The whole point of the way we do things on Downton is we don't do them gratuitously. We are interested in exploring the resultant emotions and the effect these things have on people," he said, but added he was "sorry" if fans felt the show couldn't "go there."

The episode stirred up buzz again after Sunday's airing here, with Anna fans tweeting their dismay.

One example: "Not sure I can watch Downton Abbey any more. To say that the use of rape as a plot device creeps me out is putting it mildly."

Gareth Neame, the series' executive producer, defended the story to TV Guide as being representative of the shame experienced by lower-class working women of the 1920s.

"It is not us just being flashy and trying to get attention," he says. "It is definitely something that was an issue at the time and women did not have any of the recourse that they would have now. Anna is in a terrible predicament that gives us a great undercurrent that runs through our fourth season."